In recent years color liquid crystal display panels have been used as a display panel for information communications equipment as well as for general electric equipment. In such color liquid crystal display panels, a pair of transparent substrates are bonded together with a frame-shaped sealing material therebetween, and a liquid crystal is sealed in a gap surrounded by the pair of substrates and the sealing material. One of the pair of substrates is an array substrate that has on the inner surface thereof a plurality of data lines and scan lines (gate lines) arranged in a matrix. Further, a thin film transistor is connected to the intersection of each data line and scan line, and a pixel electrode is provided at the intersection. The other substrate is a color filter substrate that has on the inner surface thereof an opposed electrode, as opposed to the abovementioned pixel electrode, and a three-color filter including R (red), G (green), and B (blue).
On the array substrate, the respective ends of the data lines and the scan lines are drawn out of the sealing material. A mounting terminal for mounting a semiconductor element for driving a liquid crystal (referred to as “IC chip”) is formed at the respective ends of these drawn-out lines. An IC chip is connected to each of these mounting terminals. A scan signal is in turn supplied to each scan line via the IC chip, and a data signal is supplied to each data line in synchronization with such scan signal supply. Thus the thin film transistor is turned on, displaying a color image.
Such a color liquid crystal display panel is subjected to an in-process inspection in which the wiring condition of each line, e.g., the presence or absence of a break or short circuit in each line, is checked, before IC chips are mounted on the panel (for example, see JP-8-201843-A).
FIG. 10 is an enlarged plan view of a part of inspection lines of a color liquid crystal display panel described in JP-8-201843-A.
In this color liquid crystal display panel 20, the data lines 22 for blue (B), the data lines 22 for green (G), and the data lines 22 for red (R) are drawn out of a side of a sealing material 21 by different lengths L1 to L3 (L1>L2>L3), respectively. Similarly, scan lines 23 are drawn out of another side of the sealing material 21 by different lengths L4 to L5 (L4>L5). Mounting terminals and 22a and 23a for mounting an IC chip are provided to the drawn-out data lines 22 and the scan lines 23, respectively. The extended ends of the drawn data lines 22 serve as inspection data lines 22R, 22G, and 22B (referred to as “inspection lines”). An in-process inspection, i.e., a lighting inspection of pixels is conducted by letting a connector touch these inspection lines.
In this lighting inspection, two connectors (first and second connectors (not shown)) are used. By disposing the first connector in the D position located on the scan lines 23, the scan lines 23 are connected to each other via the first connector. Then the lighting inspection is conducted as follows.
The second connector (now shown) is initially disposed in the A position. Disposing the connector in this position causes the connector to touch all the inspection lines 22, lighting all the pixels. If there are any pixels staying out, it can be detected that a data line is broken. Subsequently, moving the second connector to the B position causes the connector to touch the inspection lines 22B and 22G, lighting the blue and green pixels. At this point, if the red pixels are lit, it can be assumed that there is a short circuit between the data lines connected to the inspection lines 22B and 22R, or in a data line connected to the inspection lines 22R and 22G. Further, moving the second connector to the C position causes the connector to touch the inspection lines 22B alone, lighting the blue pixels and leaving the green and red pixels out. At this point, if the green pixels or the red pixels are lit, it can be assumed that a short circuit has occurred between the data lines connected to the inspection lines 22B and 22G.
In the color liquid crystal display panel described in JP-8-201843-A, the inspection lines 22R, 22G, and 22B consisting of the data lines drawn out of the sealing material 21 have different lengths depending on the color: red (R), green (G), or blue (B). Then, by moving the second connector to the three different positions A to C to conduct the lighting inspections for all and specific colors, the wiring condition of each data line is checked. However, when the length of the inspection line is changed depending on the color in this manner, for example, if the number of colors is increased, for example, to four colors: red (R), green (G), blue (B), and cyan (C), four inspection lines 22R, 22G, 22B, and 22C with different lengths from the sealing material 21 depending on the colors: red (R), green (G), blue (B), or cyan (C), are required. Consequently, the longest one (the inspection line 22C for cyan in FIG. 11) of the inspection lines consisting of the data lines drawn out of the sealing material 21 is extended further than the previous longest inspection line. Therefore, the space where the inspection lines are provided must be made larger than when the number of colors is three to a degree that the longest inspection line is extended further. Additionally, in the inspection method, the number of positions in which the connectors are placed is increased by one and thus becomes four, that is, the D position is added to the A to C positions. Therefore, when the number of color filter segments is increased in the related-art inspection method, it is necessary to increase the space where the inspection lines are provided as well as the number of man-hours for the inspection, requiring more inspection time.
In recent years, miniaturization and higher definitions have been required for this type of color liquid crystal display panels, particularly, ones that are used with cellular phones. Of these requirements, miniaturization has been addressed by devising a variety of methods, for example, making the frame narrower, laminating the peripheral wiring, or miniaturizing IC chips. Therefore, it is difficult to increase the space where the inspection lines are provided as described above. Further, when the larger number of man-hours for the inspection and more inspection time are required, the problem of reductions in panel productivity concurrently occurs.